I’m pretty sure that laughter is not the best medicine. Nonetheless, the research consistently shows that happiness has impressive medical benefits. And these benefits include improvements to the immune system.

For example, when undergraduates in a study were exposed to the rhinovirus, they got sick. (What did you expect from the virus that causes the common cold?) The interesting finding concerned the participants who had their happiness levels boosted by the researchers just before being exposed to the virus. The researchers did this in simple ways, such as by showing humorous videos. Those people who were given the happiness boost were less likely to get the cold than those who didn’t have their happiness increased. And if they did get the cold, the happier students reported that the symptoms were less severe. The study was essentially repeated with the influenza virus, which causes the flu, with the same basic results. Undergraduates who were first given the happiness boost were more resistant to the flu virus.

by epSos de/Wikimedia Commons
Source: by epSos de/Wikimedia Commons

In a more recent study, 350 adults volunteered to be exposed to the cold virus. (The subjects were compensated nicely.) The adults’ positive emotions, such as feeling energetic and pleased, were measured for two weeks before exposure to the virus. Those who reported the most positive emotions were less likely to develop the cold.

A study of dental students told a similar story. These students reported their mood three times a week for almost two months. They also had their saliva collected so that their immune systems’ effectiveness could be assessed. When the students’ immune systems were challenged by a pill containing a protein from rabbit blood, the response to this foreign material depended on the students’ moods. The response of the immune system was weaker on days marked by negative moods, and higher on days marked by positive moods.

More recently, researchers gave 81 graduate students two doses of the hepatitis B vaccine. This vaccine causes the immune system to respond. After two doses, the students rated themselves on nine positive emotions. Those who reported high levels of positive emotions had a much stronger immune response.

So is the secret to a healthy immune system as simple as smiling? Well, certainly not if those smiles are faked. When bus drivers’ smiling and moods were monitored for two weeks, researchers found that the drivers’ moods got worse and they withdrew from work when they faked smiles. And faking smiles was particularly hard on women. However, when the drivers gave more authentic smiles, by focusing on pleasant thoughts and memories, their moods and productivity improved.

Happiness is associated with many benefits, such as better relationships and a longer life. Happiness is also associated with physical changes in the immune system. So how do we increase our happiness? Check out my video series for some ideas.

You are reading

The Happiness Doctor

Does Having Children Make Us Happy?

Children do (and don't) make you happy, depending on where you live.

Three Ways Money Buys Happiness

Research shows that how we choose to spend income can increase our happiness.